226 VETERINARY SURGICAL THERAPEUTICS, 
ing them the hairless skin is covered with a dry, horny, hard and irregular 
patch, which results from the hypertrophy of the horny layer of the 
epidermis. Generally, the deep face of this core is flat, the mucous layer 
and the dermis remain intact or slightly altered; it is possible, however, 
that the papillary coat is involved in old and extensive cores, and that 
they remain even after the removal of the cause that has produced them. 
Except in rare cases, cores of our large animals are painless, and do not 
interfere with their use. It is not so with those of the paws of dogs; 
they have deep roots, which consume the papilla, thin the dermis, and 
give rise ordinarily to severe lameness. 
Cores due to the harness, most commonly giving rise to no serious im- 
pediment, are not treated; it is, however, important to prevent the in- 
crease of the trouble by improving the condition of the harness, with new 
padding, for instance. Painful cores must be relieved of all pressure. 
The thinning of the epidermic plate with the bistoury, and applications of 
vaseline, glycerine or salicylic collodion are ordinarily used. Cauterization 
with mineral acid or the excision of the cutaneous spot is seldom necessary. 
In dogs, the cores of the paws are treated with paring, warm baths, 
and the repeated applications of salicylic collodion. 
On the surfaces where the skin is much pressed by certain pieces of 
harness (saddJe, collar, surcingle), spots of dry gangrene may develop, 
of which we have already spoken in the article on Gangrene, and which 
are known as stick/asts. This expression does not apply to epidermic 
growths, but, on the contrary, to lesions of necrotic order. 
Their pathogeny is known; badly padded or improperly fitting har- 
ness presses lard on the skinand promotes a permanent ischzemia and cel- 
lular disturbance, which end in mortification of a more or less extensive 
cutaneous spot, generally circular in shape. If the pressure continues, 
the tegumentary spot, which is necrosed, dried and hardened, transmits it 
to the tissues underneath, which in turn become successively necrosed ; 
thus is explained the formation of the deep stickfasts of the withers, of 
the neck, and of the poll, accidents that we shall consider later. 
The sloughing of the mortified skin takes place asin all cases of limited 
dry gangrene. It rarely requires more than twelve or fifteen days, when 
the necrosis does not extend beyond the subcutaneous connective tissue. 
The wound heals by granulation. 
Stickfasts are prevented by watching the condition of the harness and 
its paddings. As soon as the mortification sets in, its spreading is pre- 
vented by removing the pressure made on the spot; the animal should, 
according to the case, be kept out of work for a certain length of time, or 
the harness should be so altered as to prevent any further mischief. 
Though this may often be sufficient, it is better to accelerate the cure by 
